"Such a depth means the Jiaolong is capable of reaching over 70 percent of the sea beds in the world," Xinhua said, quoting head of diving operations Wang Fei. "It will pave way for a record-breaking 7,000-meter test dive in 2012."

"At a depth of 5,000 meters, the Jiaolong withstood great pressure amounting to 5,000 tons per square meter," said Wang.

The dive, though less than half as deep as a record deep sea dive by the US Navy when it touched down at the bottom of the Mariana Trench in the Pacific Ocean in 1960, marks a significant achievement for the Chinese who are trying to catch up with advanced nations in space, sea, and polar explorations.

The current record holder for deepest manned dive is Japan's Shinkai 6500, which dived to 21,414 feet in August 1989.

Xinhua said further tests are expected, during which Chinese scientists will carry out "scientific research and further test different functions of the craft."

The Jiaolong submersible was used last year to plant China's national flag deep beneath the South China Sea, where Beijing has clashed with the United States and Southeast Asian countries over territorial border disputes.

While Jiaolong is mostly used by the seemingly civilian State Oceanic Administration, the Chinese government is developing a military submarine that will hopefully follow Jiaolong's success.

President Hu Jintao has made upgrading the navy a key element of the country's military modernization, including the development of the country's first aircraft carrier.

The Jiaolong -- designed to reach depths of 23,000 feet -- carried three people to 13,200 feet below sea level on Thursday. Its 21,414-foot dive occurred early Tuesday morning, with the same three passengers on board, said Xinhua, citing the State Oceanic Administration (SOA).

The success of the tests indicate that Jiaolong is fully capable of reaching nearly three-quarters of the planet's sea beds.

China has pushed hard in recent years to obtain oil, minerals and other natural resources needed to fuel its growth. The country says its submersible program is aimed at scientific research and the peaceful exploration and use of natural resources.

Chinese scientists say the ocean's floor contains vast amounts of rich deposits of potentially valuable minerals, but the extreme depths make it difficult to harvest them on a wide scale.

But Jian Zhimin, director of the State Key Laboratory of Marine Geology at Shanghai's Tongji University, said it now may not be long before China can begin reaching some of these riches.

"I don't think it will be a very long time before China can perform deep-sea ocean-floor mining," Jian told AFP, noting that many of the most valuable mineral resources are located around the Jiaolong's maximum designed diving limit.

The SOA said it's submersible would attempt the maximum depth dive in 2012, according to Xinhua.

Concerns have arisen over China's deep submersible program that the nation could use deep submersibles for military-related applications such as tapping into or severing communications cables.

Jiaolong's chief designer, Xu Qinan, was quoted by Xinhua as saying the "state-of-the-art" digital underwater communications systems and undersea mobility systems allowed it to "move back and forth easily under the sea."

Though most of the craft's components were produced in China, some had to be imported from abroad, such as the underwater high-definition video-shooting and transmission equipment, Xu told Xinhua.